[. . . ] [. . . ] NOTE: This hub uses uses two R4 fully sealed bearings. Smooth push-in style end cap. (B) Micro 58 New Style Screw-In 688 bearing is flush with the end of the hub. NOTE: This hub uses uses two 688 fully sealed bearings. Threaded screw-in style end cap. All repairs should be performed by a Professional Bicycle Mechanic. sales@amclassic. com 800-813-5545 www. amclassic. com [. . . ] [. . . ]